A multi-channel loop heat pipe and radiator

Abstract

The application discloses a kind of multi-channel loop heat pipe and radiator, comprising: heat pipe body and heat pipe cover, heat pipe cover is set in the open side of heat pipe body cavity;Heat pipe body has evaporation cavity and multiple condensation cavities, multiple condensation cavities are evenly distributed in the outer circumferential side of evaporation cavity, each condensation cavity is communicated with evaporation cavity by corresponding steam passage and liquid passage, to form multiple circulation heat dissipation structure, each condensation cavity and each liquid passage are provided with liquid storage cavity between.The application adopts new type loop heat pipe of multiple condensation cavities sharing an evaporation cavity, not only compact overall structure, small space occupation, and, compared with single loop, heat dissipation effect can be increased by 3-4 times, greatly improve heat dissipation capacity;And can adapt to different orientation in gravitational field and acceleration field, can be applied in high-power computing power module heat dissipation and aerospace field heat dissipation.

Description

Technical Field

[0001] This invention relates to the field of radiator technology, and more specifically to a multi-channel loop heat pipe and radiator. Background Technology

[0002] With the development of IoT, edge computing, and 5G applications, data AI is driving global computing power into a period of rapid growth. As the TDP of the new generation of servers has increased to near the limit of air cooling, especially with the relatively high thermal power consumption of domestically produced and controllable chips, such as the Huawei Kunpeng 9206U VPX module with a total board thermal power consumption of up to 280W, the high heat flux density AI chips such as GPUs and NPUs (when the board design power is higher than 300W) have high power consumption and high heat dissipation requirements. A server needs to be composed of multiple XPU board modules, as well as power supply modules, switching modules, etc., which leads to a huge increase in the heat flux density of the entire server. At the same time, in practical applications, servers are required to be small in size, with limited space and compact structure, so new thermal management designs are necessary.

[0003] Currently, high-performance chips and servers typically employ cooling methods such as forced air cooling, ordinary heat pipes, and ordinary heat pipes combined with fans. ① Air cooling uses air as a medium, dissipating heat through convection between the heat sink or fan and intermediate materials such as thermal interface materials, vapor chambers (VCs), or heat pipes. Under natural cooling conditions, a 6U VPX board module can dissipate 50-60W of power; under forced air cooling, the board's maximum power is limited to 200-300W. ② Ordinary heat pipes are a common and cost-effective cooling method with mature manufacturing processes. A traditional loop heat pipe typically consists of four parts: an evaporator, a condenser, a gas line, and a liquid line. The evaporator and condenser are connected by the vapor line and the liquid line, forming a closed loop. When the evaporator is heated, the liquid working fluid evaporates on the outer surface of the capillary wick. The generated vapor flows out from the gas line and enters the condenser under the action of density difference, where it is condensed into liquid. The condensate then flows back into the evaporator through the liquid line under the capillary pressure generated by the capillary wick for re-evaporation. This cycle of heat exchange and transfer continues. Throughout the entire process, the capillary wick in the evaporator is the important power source and core component of the entire system cycle.

[0004] However, traditional loop heat pipes still have some drawbacks, mainly twofold: obstructed vapor flow and "burn-out." Obstructed vapor flow typically occurs during the startup of the loop heat pipe. When starting up, the evaporator heats up and generates vapor, requiring new liquid working fluid to be added from the liquid line under the suction force of the capillary wick. However, when vapor flow is obstructed, the vaporized working fluid cannot flow out of the evaporator and is instead forced back into the capillary wick, resulting in a "backflow" phenomenon. This backflowing vapor clogs the capillary structure and hinders the return flow of the liquid working fluid, preventing smooth circulation. Furthermore, sudden changes in operating conditions during the operation of a traditional loop heat pipe, such as a sudden increase in heating power, can also lead to backflow, causing the heat pipe to stop working. "Burning dry" usually occurs during operation. When the loop heat pipe is running, as the heating power increases, insufficient capillary suction or low system liquid filling rate can cause the liquid working medium in the capillary to decrease to dryness. At this time, the "burning dry" phenomenon occurs, which causes the temperature of the inner wall of the evaporator to rise sharply. Traditional loop heat pipes cannot work properly or may even be damaged.

[0005] Furthermore, traditional loop heat pipes are only a single loop, resulting in low heat dissipation efficiency. In addition, when traditional loop heat pipes are used in scenarios with changing gravitational and acceleration fields, the vapor or liquid pipelines are in different orientations. Due to the influence of gravity, the vapor and liquid in the pipe cannot quickly enter the condenser and evaporator respectively, thus affecting the heat dissipation efficiency. This makes traditional single-loop pipes unsuitable for gravitational and acceleration fields, such as in aerospace applications.

[0006] Therefore, how to provide a multi-channel loop heat pipe and radiator that not only has good heat dissipation effect, but can also be used for heat dissipation of high computing power chips and aerospace fields, overcomes gravitational field and acceleration field, thereby improving the applicability of heat pipe; and can ensure that the capillary wick of the evaporator has sufficient liquid reserve and supply, reduce the phenomenon of "burning dry" of the evaporator and ensure smooth circulation of working fluid is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a multi-channel loop heat pipe and radiator that not only has good heat dissipation effect, but can also be used for heat dissipation of high computing power chips and aerospace fields, overcomes gravitational field and acceleration field, thereby improving the applicability of heat pipe; and enables the capillary wick of evaporator to have sufficient liquid reserve and supply, reducing the phenomenon of "burning dry" of evaporator and ensuring smooth circulation of working fluid.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A multi-channel loop heat pipe includes: a heat pipe body and a heat pipe cover plate, wherein the heat pipe cover plate is disposed on the open side of the heat pipe body cavity;

[0010] The heat pipe body has an evaporation chamber and multiple condensation chambers. The multiple condensation chambers are evenly distributed on the outer periphery of the evaporation chamber. Each condensation chamber is connected to the evaporation chamber through corresponding vapor and liquid channels to form a multi-circulation heat dissipation structure.

[0011] Each of the condensation chambers and each of the liquid channels is provided with a liquid storage chamber.

[0012] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a multi-channel loop heat pipe, which adopts a novel loop heat pipe in which multiple condensing chambers share one evaporating chamber. Not only is the overall structure compact and occupies little space, but the heat dissipation effect can be increased by 3-4 times compared with a single loop, greatly improving the heat dissipation capacity. In addition, the multiple condensing chambers are evenly and symmetrically arranged, which can adapt to different orientations in gravitational and acceleration fields. This overcomes the defect of traditional heat pipes that use a single loop, where steam or liquid in the steam or liquid pipeline is easily affected by gravity and cannot enter the condensing chamber and evaporating chamber quickly and separately, thus affecting the heat dissipation efficiency. Therefore, this multi-channel loop heat pipe can be used in the heat dissipation of high-performance chips and aerospace fields, with a wide range of applications. Furthermore, the built-in liquid storage chamber ensures sufficient liquid reserve and supply to the capillary wick in the evaporation chamber, reducing the risk of "burning out" and ensuring normal gas-liquid circulation along a predetermined path. It also reduces gas backflow or the presence of non-condensable gases in the evaporation chamber, preventing gas blockage in the liquid channel that could hinder liquid supply to the capillary wick. This addresses issues such as unstable startup and operational adaptability at excessively high temperatures. Currently, this invention has successfully passed high-temperature testing (60℃) and is operating stably and reliably in high-performance servers.

[0013] Furthermore, both the evaporation chamber and the condensation chamber are provided with multiple ribs.

[0014] The beneficial effects of adopting the above technical solution are: the fins increase the heat exchange area during evaporation and condensation, thereby improving the evaporation and condensation rates and resulting in better heat dissipation of the loop heat pipe. Furthermore, the fins increase the overlap area between the heat pipe body and the heat pipe cover, facilitating welding and resulting in less welding deformation and a higher yield.

[0015] Furthermore, both the heat pipe body and the heat pipe cover are flat plate structures.

[0016] The beneficial effects of adopting the above technical solution are: it increases the heat exchange area of ​​the evaporation chamber, condensation chamber, steam channel and liquid channel, thereby improving the high heat absorption and high heat dissipation of the loop heat pipe.

[0017] Furthermore, the width of the condensation chamber is greater than the width of the vapor channel and the liquid channel.

[0018] The beneficial effects of adopting the above technical solution are: increasing the heat exchange area of ​​the condensing chamber and improving the condensation capacity.

[0019] Furthermore, the liquid storage chamber is located at the end of the condensation chamber.

[0020] The beneficial effects of adopting the above technical solution are: after the steam turns into liquid in the condensation chamber, it continuously accumulates and buffers in the liquid storage chamber, ensuring that the capillary wick in the evaporation chamber has a sufficient liquid supply, avoiding the "burning dry" phenomenon in the evaporation chamber, which would lead to a sharp rise in the temperature of the inner wall of the evaporator, causing the traditional loop heat pipe to malfunction or even be damaged.

[0021] The present invention provides a heat sink, including a heat sink body and a multi-channel loop heat pipe. The heat pipe body and the heat sink body are fixed together by welding or thermally conductive silicone adhesive to ensure full contact between the multi-channel loop heat pipe and the heat sink body and increase the efficient heat transfer effect between the two.

[0022] Furthermore, the heat sink body is made of anodized aluminum alloy, and the heat pipe body is made of copper plated with nickel and tin, and the two are welded at low temperature.

[0023] The beneficial effects of adopting the above technical solution are: through the above treatment, the heat sink body with different melting points can be welded to the heat pipe body, and the problem of electrochemical corrosion caused by the potential difference between the two in direct contact can be effectively avoided.

[0024] Furthermore, the radiator body is provided with a pull-out aid and a wedge-shaped locking strip.

[0025] The high-efficiency multi-channel loop heat pipe of this invention solves the technical problems of high heat flux density, limited space, and large heat power consumption of high-performance servers in the era of intelligent computing. It can also be applied to high heat flux density AI chips such as GPUs and NPUs (when the board design power is higher than 300W), with broad market prospects and huge economic potential. At the same time, the multiple condensation chambers are symmetrically designed, which can adapt to different orientations in gravitational or acceleration fields, and can also be applied in the aerospace field. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1This is a schematic diagram of a multi-channel loop heat pipe provided by the present invention.

[0028] Figure 2 This is a schematic diagram of the main body of the heat pipe.

[0029] Figure 3 This is a schematic diagram of a multi-channel loop heat pipe installed on the heat sink body.

[0030] Figure 4 This is a schematic diagram of the structure of a multi-channel loop heat pipe and the radiator body exploding.

[0031] Figure 5 This is a schematic diagram showing a radiator body equipped with a pull-out aid and a wedge-shaped locking strip.

[0032] Figure 6 This is a first-person view diagram of the radiator assembly.

[0033] Figure 7 This is a second-view diagram of the radiator assembly. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figures 1-2 As shown, an embodiment of the present invention discloses a multi-channel loop heat pipe, including: a heat pipe body 1 and a heat pipe cover plate 2, wherein the heat pipe cover plate 2 is disposed on the open side of the cavity of the heat pipe body 1;

[0036] The heat pipe body 1 has an evaporation chamber 11 and multiple condensation chambers 12. The multiple condensation chambers 12 are evenly distributed on the outer periphery of the evaporation chamber 11. Each condensation chamber 12 is connected to the evaporation chamber 11 through a corresponding vapor channel 13 and a liquid channel 14 to form a multi-circulation heat dissipation structure.

[0037] Each condensation chamber 12 and each liquid channel 14 is provided with a liquid storage chamber 15.

[0038] Multiple fins 16 are provided in both the evaporation chamber 11 and the condensation chamber 12.

[0039] Both the heat pipe body 1 and the heat pipe cover plate 2 are flat plate structures.

[0040] The width of the condensation chamber 12 is greater than the width of the steam passage 13 and the liquid passage 14.

[0041] The liquid storage chamber 15 is located at the end of the condensation chamber 12.

[0042] like Figures 3-5 As shown, a heat sink of the present invention includes a heat sink body 3 and a multi-channel loop heat pipe. The heat pipe body 1 and the heat sink body 3 are fixed by welding or by bonding with thermally conductive silicone.

[0043] The heat sink body 3 is made of anodized aluminum alloy, and the heat pipe body 1 is made of copper plated with nickel and tin. The edges of the two are welded at low temperature. Finally, holes for degassing, pressure extraction, and working fluid filling are processed. After vacuuming and filling with working fluid, the heat pipe is sealed and inspected.

[0044] The heat sink body 3 calculates the surface area of ​​the heat sink fins based on the temperature difference between the heat sink fins and the inlet and outlet of the heat sink fins, the convective heat transfer coefficient, the ventilation volume, the specific heat of the air, and the total heat generated by the chip. This ensures that, under forced air cooling, it can reliably and timely dissipate the heat generated by each heat-generating device in the module to the heat sink. In addition, the heat sink body 3 is equipped with a pull-out aid 4 and a wedge-shaped locking strip 5.

[0045] The working principle of the multi-channel loop heat pipe of the present invention is as follows: after the cooling medium is heated and evaporated into gas in the evaporation chamber, it flows into the condensation chamber in the form of gas through the vapor channel under the action of the capillary wick. After the cooling medium is cooled, it becomes liquid and flows into the liquid storage chamber. Then, it flows into the evaporation chamber in the form of liquid through the liquid channel, completing one cycle. The cooling medium can circulate repeatedly in each channel loop heat pipe, thereby achieving a highly efficient heat dissipation and cooling effect.

[0046] The multi-channel loop heat pipe of the present invention can adopt a four-channel loop heat pipe with symmetrical top, bottom and left and right sides. It is mainly used for heat dissipation of high power computing modules. It mainly consists of a computing module heat sink body and a four-channel loop heat pipe. The working principle is that the four-channel loop heat pipe absorbs the heat generated by the thermal power devices in the computing module and quickly conducts it to the module heat sink body. The heat can be dissipated to the heat sink through the forced fan of the module mounting box or through liquid cooling, thereby ensuring that the thermal power devices in the computing module can work stably and reliably.

[0047] In addition, the four condensation chambers of this invention share one evaporation chamber and have a heat dissipation structure that is symmetrical from left to right and from top to bottom. This innovation not only expands the evaporator area and increases the number of heat dissipation capillary loops (4), but also makes the overall structure more compact. The heat dissipation effect is 3 to 4 times greater than that of a single loop. It can adapt to different orientations in gravitational and acceleration fields and overcome the gravitational influence of steam in a single orientation. It can guide its application in the aerospace field.

[0048] Meanwhile, a liquid storage chamber is designed in the condensation chamber of each loop to store liquid, ensuring sufficient liquid reserve and supply in the capillary wick of the evaporation chamber, ensuring that the vapor and liquid flow along the predetermined path, and reducing gas backflow or the presence of non-condensable gases in the evaporation chamber. This also prevents gas blockage in the liquid channel from hindering the liquid supply to the capillary wick of the evaporation chamber, solves problems such as unstable start-up, and addresses the issue of adaptability to operation under excessively high temperatures.

[0049] The present invention incorporates capillary wicks in the evaporation chamber, condensation chamber, steam channel, and liquid channel to increase the circulation capacity of the multi-channel loop.

[0050] The selection and proportioning of the cooling medium in this invention: First, a suitable working medium should be selected based on the operating temperature range of the loop heat pipe radiator. Within the operating temperature range, the working medium must exist in a gas-liquid two-phase state; that is, the lowest operating temperature of the loop heat pipe radiator should be higher than the freezing point of the working medium, while the highest operating temperature should be lower than the critical temperature of the working medium. Otherwise, the working medium will freeze in the loop or fail to undergo phase change, thus the loop heat pipe radiator will not operate normally. This invention innovates upon the traditional ammonia working medium. Given that ammonia has a melting point of -77.75℃ and a boiling point of -33.5℃ at room temperature and pressure, it is necessary to appropriately increase the amount of coolant (such as No. 65 coolant, whose freezing point is -65℃). The cooling medium of this invention uses a 55:45 ratio of ammonia to No. 65 coolant, ensuring that the newly proportioned coolant does not solidify at -65℃ and vaporizes at around 55℃, thus improving the heat absorption capacity and heat dissipation speed of the cooling medium, achieving stable, reliable, and efficient heat conduction.

[0051] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0052] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-channel loop heat pipe, characterized by, include: A heat pipe body (1) and a heat pipe cover plate (2), wherein the heat pipe cover plate (2) is disposed on the open side of the cavity of the heat pipe body (1); The heat pipe body (1) has an evaporation chamber (11) and four condensation chambers (12). The four condensation chambers (12) are distributed on the outer periphery of the evaporation chamber (11). Each condensation chamber (12) is connected to the evaporation chamber (11) through a corresponding vapor channel (13) and a liquid channel (14). The evaporation chamber (11) is roughly rectangular and has four vapor channels (13) and four liquid channels (14) distributed on its outer periphery. One corner of the evaporation chamber (11) is connected to two vapor channels (13) or two liquid channels (14). The four vapor channels (13) are distributed at one corner of the evaporation chamber (11), and the four liquid channels (14) are distributed at the other corner of the evaporation chamber (11) to form a multi-cycle heat dissipation structure. A liquid storage chamber (15) is provided between each of the condensation chambers (12) and each of the liquid channels (14); The width of the condensation chamber (12) is greater than the width of the steam passage (13) and the liquid passage (14); The liquid storage chamber (15) is located at the end of the condensation chamber (12).

2. A multi-channel loop heat pipe according to claim 1, wherein Both the evaporation chamber (11) and the condensation chamber (12) are provided with multiple ribs (16).

3. A multi-channel loop heat pipe according to claim 1, wherein Both the heat pipe body (1) and the heat pipe cover plate (2) are flat plate structures.

4. A heat sink, characterized by It includes a heat sink body (3) and a multi-channel loop heat pipe as described in any one of claims 1-3, wherein the heat pipe body (1) and the heat sink body (3) are fixed by welding or by bonding with thermally conductive silicone.

5. A heat sink according to claim 4, wherein The heat sink body (3) is made of anodized aluminum alloy, and the heat pipe body (1) is made of copper plated with nickel and tin. The two are welded at low temperature.

6. The heat sink of claim 4, wherein, The radiator body (3) is provided with a pull-out aid (4) and a wedge-shaped locking strip (5).

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